Inside pipe cutter



Nov. 17, 1953 D. w. OSMUN 2,659,434

INSIDE PIPE CUTTER Filed Oct 50' 7 2 Sheets-s l Nov.

Filed Oct. 30, 1947 D. W. OSMUN INSIDE PIPE CUTTER 2 Sheets-Sheet 2 Patented Nov. 17, 1953 UNITED STATES ATENT OFFICE This invention relates ter.

An object of the tool to an inside pipe cutdesired elevation, may be operated to sever the pipe so that the out 01f section may be removed from the well.

Another object of the invention is to provide, in a pipe cutter of the character described, novel means for retaining the cutter in inactive position with the bits, or cutters, retracted while going in and which may be released by manipulation of the operating string to allow said cutters, r bits, to be expanded into contact with severed by the rotation and cutter body.

The tool also embodies a novel type of expander, assembled in a novel manner with the cutter body and which may be readily assembled with said body or readily removed from the body for replacements or repairs.

Other objects and advantages will be apparent from the following specification which. is illustrated by the accompanying drawings, wherein:

Figure 1 is a side elevation of the tool shown in inactive position.

Figure 2 is an enlarged, fragmentary, vertical sectional view of the upper end of the tool shown in inactive position.

Figure 3 is an enlarged, fragmentary, vertical sectional view of the lower end of the tool shown in inactive position.

Figure 4 is a cross-sectional view taken on the line 44 of Figure 2.

Figure 5 is a cross-sectional view taken on the line 55 of Figure 2.

Figure 6 is a cross-sectional view taken on the line 6-6 of Figure 3.

Figure 7 is a side view, partly in section, of the upper end of the tool shown in active position.

Figure 8 is a side view of the lower end of the tool in active position and shown partly in section.

Figure 9 is a ployed, and

Figure 10 is a sectional view of the cutter body taken on the line |0I0 of Figure 2.

Referring now more particularly to the drawings wherein like numerals of reference designate similar parts in each of the figures, the numeral I designates the cutter body as a whole Whose upper end is attached to an operating plan view of a locking ring emstring 2.

This string extends to the ground surface and may be tubular if desired.

diameter forming a stem 4.

The lower end of the head is provided with in radial shoulders 5.

Pinned in the upper ends of the slots 5 and abutting the corresponding shoulder 5 are the bearing blocks 1 whose lower ends are formed with arcuate bearing faces 8.

In the slots 5 are the swinging cutters 9 whose lower ends terminate in outwardly directed cutting bits It.

to be broken.

Spaced beneath on down the stem 4 forming notches, as l3, through said rib.

Any selected number of slots 5 and cutters 9 may be employed. Preferably there will be three, as indicated in Figure 4.

Beneath the rib l2 duced in diameter and is formed with an exbetween the rib I2 and the ring IS.

The numeral l7 designates a tubular housing whose lower end is reduced internally, in diameter forming an internal annular shoulder M3 on which the ring [5 rests when the tool is in its inactive position.

There are the cutter expanders H] which are seated in the slots 5 beneath the cutters 9. Their the upwardly and inwardly tapering faces 2| to engage behind the cutters to expand them. These shoulders 26 rest on the locking ring 22 which surrounds the stem 4.

The expanders have the downwardly extended shanks 23 whose lower ends are outwardly widened forming the shoulders 24 which register with the rib |2 when the parts are assembled.

Surrounding the shanks 23 there is a split bushing 25 which is formed in two similar halves fitted together and whose lower ends are outwardly threaded. The upper end of the split bushing is formed with an outwardly widened flange 26 which fits between the locking ring 22 and the upper end of the housing l1, as shown in Figure 2.

In assembling this expander assembly the expanders W are fitted into the corresponding slots 5 and the locking ring 22 is then passed upwardly over the stem 4 and positioned so that the inwardly extended projections 21 of the ring 22 will pass through the notches l3 and said ring may then be turned so that the projections 2'! will be out of the slots 5. The shanks of the expanders 9 may then be fitted down through the ring 22 and located'in the slots 5 and the split bushing 25 may then be assembled resting on the shoulders 24. The upper end of the housing may then be screwed onto the lower end of the split bushing 25 up against the flange 26 thereof so as to secure said parts in assembled relation with the spring 16 assembled within the housing, as hereinabove explained.

Mounted on the stem 4 and spaced beneath the housing there is a spool shaped anchor 28 and spaced beneath the anchor 28 there is an anchor ring 29.

Outwardly bowed springs 3|) are secured at their upper ends to the anchor 28 and at their lower ends to the anchor ring 29. These bow springs frictionally engage the stuck pipe 3| as the tool is lowered therein, as shown in Figure 8.

The lower end of the stem 4 is reduced in diameter and externally threaded and screwed into the enlarged upper end 32 of the guide rod 33. This guide rod is slidable through the anchor ring 29 and secured on its lower end there is a guide 34 which is of a diameter to fit, rather closely, within the pipe 3| Screwed onto the reduced lower end of the stem 4 there is a bushing 35 whose upper end is in abutting relation with an external shoulder 36 formed by the reduction of the lower end of the stem 4, and whose lower end is in abutting relation with the enlarged upper end 32 of the rod 33 when the tool is assembled and in inactive position.

This bushing 35 is formed with coarse external threads 31 which are threaded into corresponding internal threads 38 in the lower end of the anchor 28 so as to hold the stem 4 in its upper position relative to the anchor 28 when the tool is in inactive position.

Loosely connected to the upper end of the anchor 28 and upstanding therefrom there are the pipe engaging, wedge shaped slips 38, three of said slips being shown in the present illustration. Their outer sides are curved to conform to the contour of and to fit against the pipe 3| and their inner sides are formed with the upwardly and outwardly tapering faces 48.

The lower end of the housing l1 has the external upwardly flared faces 4| against which the inner faces 43 slide, as is indicated in Figure 2, and the slips 33 have sliding dovetailed connections, as 2, with the expander faces of the housing H.

The tool may be assembled as illustrated in Figures 1, 2 and 3, and as so assembled may be lowered into the well bore and into the pipe 3% pension of the spring l6 to be severed. While being lowered the friction springs 30 will ride in frictional contact with the pipe 3| but the cutter expanders |9 will be maintained in their lower, inactive position.

As will be observed from an inspection of Figure 7, the joints of the pipe 3| are internally upset thus forming an inside downwardly tapering shoulder 43.

When a point has been reached at which it is desired to make a cut the operating string 2 together with the stem 4 may be turned to the right and the bushing 35 will be unscrewed from the anchor 23, said anchor being held against turning by the springs 39 and thereupon the operating string and stem may be lowered. As the string and stem are lowered the slips 39 will be forced downwardly in the pipe 3| until the external downwardly and inwardly tapering faces 44 of said slips land on the shoulder 43 at the coupling whereupon the downward movement of said slips will be stopped but the housing l1 will move on downwardly until its downwardly tapering faces 4| expand the slips 39 into secure engagement with the pipe 3i. This will stop the downward movement of the housing I1 and, upon further downward movement of the head 3 and stem 4, the cutter expanders i9 and the expander faces 2i will act against the lower ends of the cutters 9 to force said cutters gradually outwardly.

Meanwhile the tool is being rotated and as the cutters are forced outwardly they will gradually sever the pipe 3|, as shown in Figure '1.

During the operation above described the bits iii will be held out of contact with the pipe 3| until the slips 39 have been securely engaged with the pipe 3| by downward movement of the stem a in the housing against the pressure of the spring It so that said bits will not be brought into cutting engagement with the pipe until the housing has first been securely anchored against downward movement in the pipe.

Upon completion of the cut the operating string may be pulled upwardly thus releasing the cutters 9 from the cutter expanders l9 and the exwill move the housing upwardly permitting contraction of the slips 39 and the tool may then be withdrawn through the cutoif section of pipe above and said severed section may then be removed from the well.

The drawings and description disclose what is now considered to be a preferred form of the invention by way of illustration only while the broad principle of the invention will be defined by the appended. claims.

What I claim is:

1. In an inside pipe cutter having a head, a reduced stem depending from the head and outwardly movable cutters pivoted on the head, a cutter expanding assembly on the stem comprising, a housing around the stem, longitudinally extending cutter expanders slidably mounted on said stem, said expanders having reduced shanks and outwardly thickened portions forming downwardly facing shoulders, a ring around said shanks whose upper face is engageable with said shoulders, a cylindrical bushing comprising a plurality of arcuate parts around the shanks and onto which the upper end of the housing is threaded, the upper end of said bushing being engageable with the lower face of said ring to clamp the ring between the bushing and said shoulders, an anchor beneath the housing having a threadable connection with the stem, means on the anchor engageable with the pipe to hold the anchor against rotation upon rotation of the stem whereby the stem may be 1m the pipe to hold the anchor against rotation screwed from the anchor and moved downwardly upon rotation of the stem whereby the stem may relative to the anchor, means engageable with be unscrewed from the anchor and moved downthe pipe, upon such downward movement and wardly relative to the anchor, means engageable supporting said housing against downward move- 5 with the pipe upon such downward movement ment in the pipe, and resilient means carried by and supporting said housing against downward the housing and engageable with the stem to movement in the pipe, and resilient means caryieldingly resist downward movement of the stem ried by the housing and engageable with the in the housing, said expanderbeing engageable stem to yieldably resist downward movement of with the cutters to move the cutters outwardly n the stem in the housing, said expanders being of the stem upon downward movement of the engageable with the cutters to move the cutters stem in the housing to expand the cutters into outwardly of the stem upon downward movecutting engagement with the pipe. ment of the stem in the housing to expand the 2. In an inside pipe cutter having a head, a cutters into cutting engagement with the pipe.

reduced stem depending from the head and out- 15 DEAN W. OSMUN.

wardly movable cutters pivoted on the head, a

cutter expanding assembly on the stem compris- References Cited in the file of this patent ing, a housing around the stem, longitudinally UNITED STATES PATENTS extending cutter expanders slidably mounted on said stem, said expanders having reduced shanks, Number Name Date a ring around the shanks, a cylindrical bushing 1,577,474 Le Bus 23, 1925 comprising a plurality of arcuate parts around 1,867,289 Ventresca July 1932 the shanks and onto which the upper end of the 1398-804 m et 1935 housing is threaded, an anchor beneath the 2108'330 15, 1933 housing having a threadable connection with 25 2,351,929 Davldson June 20,1944

the stem, means on the anchor engageable with 

